Background and aim Prior epidemiological studies suggest an association between talc exposure of workers and increased risks of stomach cancer. A meta-analysis was performed to evaluate this suspected association.

Methods We searched the MEDLINE, EMBASE, through 2015 for a meta-analysis examining the association between talc exposure of workers and increased risks of stomach cancer. We also searched the China National Knowledge Infrastructure (CNKI) database and Wanfang Data, because many studies on talc exposure of workers have been published in Chinese journals only. Data from observational studies were pooled using a general variance based meta-analytic method. The outcome of interest was a summary standardised mortality ratios (SMRs) reflecting the risk of stomach cancer death associated with talc exposure of workers.

Results Ten observational studies with 11 cohorts meeting protocol specified inclusion criteria were located via a comprehensive literature search. Analysis for heterogeneity demonstrated that the data were homogeneous (p = 0.8664). Pooling all cohorts yielded a summary SMR of 1.23 (CI = 1.05–1.44, p = 0.0123) for stomach cancer among workers exposed to talc, showing a 23% increase in stomach cancer mortality for these workers compared to general population. Subgroup analysis for co-exposures contamination showed no significant difference on stomach cancer SMRs between workers exposed to talc with and without asbestos contamination (p = 0.8067 under fixed effect model and random effect model), showing no significance in the confounding factor.

Conclusion The available observational data support the existence of a causal relationship between talc exposure and increased risks of stomach cancer.